JPH07314572A - Solid tire for bicycle - Google Patents

Abstract

PURPOSE:To provide a solid tire for a bicycle light in weight, hardly released upon running since the tire is fitted strongly into a rim by elastic force and permitting replacement. CONSTITUTION:A solid tire 1 for a bicycle includes a tread section 2, a cushion section 3 and a projected wheel mounting section 4, which are formed of foamed elastomer. A tension resistaing body 5, selected from rope, fabric and non-woven fabric which are consisting of organic fibers, is laminated on the inner peripheral surface of the wheel mounting section 4. The tensile characteristics of the tension resisting body 5 is provided with an elongation upon breakage, which is at least higher than 3.0%, a stress restoring characteristic higher than 1.0% upon releasing tensile stress and a tensile strength higher than 50kg.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-puncture bicycle tire used for wheelchairs, bicycles, toys and the like, and more particularly to a non-puncture bicycle tire which is difficult to detach from the wheel during traveling and can be easily replaced. .

[0002]

2. Description of the Related Art Conventionally, bicycle tires have been required to have a function of acting as a spring, absorbing a shock from the road and supporting a load. Pneumatic tires called pneumatic tires are excellent in these functions, but have the biggest drawback of flat tires. On the other hand, some solid tires and semi-pneumatic tires with various structures are used as non-puncture tires, but these tires use the elasticity of rubber itself and are generally used due to their heavy weight and poor cushioning. The current situation is that it has not been done.

In order to remedy the drawbacks of this solid tire, a non-puncture using a foamed elastomer has been proposed to reduce the weight and improve the cushioning property. For example, a non-punctured tire using polyurethane foam has a structure in which a tensile body is embedded in polyurethane foam as disclosed in US Pat. No. 4,446,903.

[0004]

However, the non-puncture tire using the foamed elastomer has a tensile body and thus is difficult to be stretched, so that it is difficult to mount it on the rim and replace the tire. Therefore, for attachment to the rim, a method of adhesively fixing the tire to the rim or a method of fitting the tire to a special rim is known. The method of adhesive fixing has a drawback that it is almost impossible to replace the tire.On the other hand, the method of fitting to the rim uses the tensile elasticity of the tire itself for fitting, so that the tire does not separate from the rim during running. There was a drawback that it was easy to do, and a special rim shape was required. Further, by lowering the foaming ratio of the foamed elastomer and increasing the elastic modulus of the tire, the fitting force to the rim is improved, but the problem of increasing the tire weight still remains.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a replaceable non-puncture bicycle tire which is light in weight, and which is elastically fitted to the rim so as not to come off during traveling. And

[0006]

That is, the features of the present invention are as follows:
A non-puncture bicycle tire having a tread portion, a cushion portion, and a protruding wheel mounting portion formed of a foamed elastomer, wherein a tensile member selected from a rope, a woven fabric, and a non-woven fabric made of an organic fiber is provided on an inner peripheral surface of the wheel mounting portion. Non-puncture having a tensile strength of the tensile member of at least 3.0% or more at break, a strain recovery property of 1.0% or more when the tensile stress is released, and a tensile strength of 50 kg or more. It's on a bicycle tire.

FIG. 1 is a sectional view of a non-puncture bicycle tire of the present invention. The non-puncture bicycle tire 1 includes a tread portion 2, a cushion portion 3, and a wheel mounting portion 4 protruding inward. Each of these parts is formed from a foamed elastomer. A pair of tension bodies 5 made of canvas for preventing the tire from coming off are laminated on the wheel mounting portion 4 on the inner peripheral surface of the wheel mounting portion 4.

In the non-puncture bicycle tire 1 shown in FIG. 2, there is shown a case where the foaming ratios of the foamed elastomers of the tread portion 2 and the cushion portion 3 are different. Specifically, the tread portion 2 has a density of 0.6 to 1.2 g / cm ³ and a non-foaming or low foaming elastomer having a foaming ratio of 0 to 2 times, while the cushion portion 3 has a density of 0.3 to 0. .6 g / c
The foamable elastomer having a foaming ratio of 2 to 4 times m ³ has a density of 0.3 to 0.
A foamable elastomer having a foaming ratio of 2 to 4 times at 6 g / cm ³ is provided. Further, a tension member 5 made of rope for preventing the tire from coming off is laminated on the inner peripheral surface of the wheel mounting portion 4. In this case, the boundary between the tread portion 2 and the cushion portion 3 is a straight line. Also, the tread portion 2
Is 10 to 30% of the tire cross-sectional area, and 10%
When it is less than the above range, it is impossible to cover the entire ground plane, and when it exceeds 30%, it becomes too heavy.

The tensile strength of the tensile member 5 is at least 3.0% or more, preferably 5.0% or more in elongation at break, and 1.0% or more when tensile stress is released, preferably 3.
It has a strain recovery characteristic of 0% or more and a tensile strength of 50 kg or more. As a concrete tensile body 5,
It is made of rope made of natural fiber, polyamide fiber, polyester fiber, woven fabric, non-woven fabric, foamed elastomer in which short fibers are dispersed and mixed.

As the foamed elastomer used in the present invention, there is foamed polyurethane, which is basically divided into two components of polyol type and isocyanate type and used by mixing and stirring before injection. The polyol type is mainly composed of polypropylene glycol or polytetramethylene glycol having a molecular weight of 1,000 to 7,000 as a high molecular weight polyol, ethylene glycol as a chain extender, 1.4
A low molecular weight polyol such as butanediol and trimethylolpropane, a tertiary amine as a catalyst, and organic tin are added. As the foaming agent, an organic solvent such as chlorofluorocarbon, methylene chloride or pentane is used, but environmentally friendly water is preferably used. In addition, a small amount of pigment and a foam stabilizer such as silicone are added to the polyol system.

The isocyanate type is 2.4-toluene diisocyanate, 2.6-toluene diisocyanate,
1.5-naphthalene diisocyanate, hexamethylene diisocyanate, 4.4'-diphenylmethane diisocyanate (pure MDI), polymeric MDI
(Crude MDI) and the like, and normally, a liquid obtained by modifying 4,4′-diphenylmethane diisocyanate (MDI) is used. Examples of the modification method include a method of reacting with a low molecular weight polyol to form a prepolymer, and a method of dimerizing (carbodiimide).

As the other foamed elastomer, a vulcanizing agent, a reinforcing material and a foaming agent are added to natural rubber, synthetic rubber or other mixture.

FIG. 3 is a sectional view of an apparatus for manufacturing a non-puncture bicycle tire using foamed polyurethane, and FIG. 4 shows a part of a partially enlarged view of FIG. The mold 10 is composed of a ring-shaped split mold 12 and another ring-shaped split mold 12 having a cross-shaped arm 13, and the split molds 12 and 12 can be opened and closed by a clamp 15. A rotating shaft 16 is inserted in the center of the mold 10, and the mold 10 is rotated by a rotation of a prime mover 17 via a transmission belt 18. A slit portion 20 of 1 to 5 mm for injecting the foamed elastomer is provided all around the inside of the mold 10, so that the foamed elastomer is injected into the cavity 21 in the mold from the slit portion 20 of the rotating mold 10. It has become. And on both sides of the slit portion 21,
A pair of tensile bodies 5 for preventing tire detachment are mounted on the inner peripheral surface of the mold 10.

In the case of this casting, the foamed elastomer is once put in a receiver such as a funnel 23 and then injected, or the undiluted solution injection section is widened, and from there, it is guided to the slit section 20 by a centrifugal force and is introduced into the cavity 21. It is also possible to throw in. When the foamed elastomer has been cast, the slit portion 21 is closed by the shut ring operating rod 25.
When manufacturing the non-puncture bicycle tire 1 shown in FIG. 2, the tread portion 2 and the cushion portion 3 are made of elastomer stock solutions having different expansion ratios, and the elastomer forming the tread portion 2 is first injected. After rotational molding, the elastomer forming the cushion portion 3 can be injected to perform rotational molding.

Rotation of the mold 10 is preferably performed in a vertical plane from the viewpoint of eliminating the lateral deviation of the tread portion 2. However, when giving a rotation of 5 G or more, it does not matter even in a horizontal plane. The mold rotation is required only for the time from the injection to the time when the urethane stock solution is solidified, and a centrifugal force of 2 G or more is required for rapid dispersion of the material in the cavity 21.

The material of the mold 10 may be any of resin, ZAS, aluminum, steel, etc., but a lightweight one is preferable because it is rotated.

[0017]

In the non-puncture bicycle tire of the present invention, the foamed elastomer is excellent in cushioning properties for absorbing impact from the road surface and in weight reduction, and a tensile body made of a material having a large recovery force when tensile stress is released is laminated. By integrating them, it is possible to increase the force of fitting to the rim and prevent the tire from coming off during traveling.

[0018]

The present invention will be described in more detail with reference to the following examples. Example 1 The same mold as that shown in FIGS. 3 and 4 having a slit portion with a width of 3 mm was used. The mold had a diameter of 673 mm and a peripheral length of 2113 mm. After heating this mold to 40 ° C and applying an oil-based release agent by spraying, a pair of ropes, which are tensile members that are reinforcing materials for preventing tire detachment, are wrapped around the inner peripheral surface of one split mold. It was This rope is polyethylene terephthalate fiber, and the structure is 1100d / 2.
X5, and the number of twists is 16 times of the upper twist (Z) / 10 cm,
The lower twist is 27 times / 10 cm. The tensile properties are an elongation at break of 14.5% and a tensile strength of 83 kg / piece.

After closing the split mold with a clamp, the mold was rotated at 100 rpm (about 3.4 G) in a vertical plane to obtain polypropylene glycol (trifunctional, molecular weight 6,000).
100 parts by weight, ethylene glycol 9 parts by weight, water 0.6
Parts by weight, catalyst (tertiary amine) 0.6 parts by weight, MDI87
The ingredients of the formulation consisting of parts by weight were mixed and stirred, 800 g was injected through the slit, and rotation was continued for 3 minutes after the injection. Then, the non-puncture bicycle tire made of expanded polyeleun was released from the mold by crosslinking and foaming for 20 minutes.

The non-puncture bicycle tire produced in this manner had a sufficient fitting force when fitted to a WO type rim for a pneumatic tire while being stretched, and did not come off during running.

Example 2 A belt-shaped 6.6 nylon canvas cloth having a width of 8 mm was sewn with a sewing machine to form 5 pieces.
A ring formed of 57 to 562 mm was used as a tensile body. This canvas is plain weave and weft 420d
/ 3 yarns, twist number 15 times / 10 cm, yarn density is 75 yarns / 15 cm, weft 50 yarns / 15 cm. Also,
The tensile properties of this canvas are an elongation at break of 18.5% and a tensile strength of 89 kg / piece. A polyurethane foam non-puncture tire for a bicycle was obtained using the above-mentioned canvas using the same type and urethane composition as in Example 1. This tire, which was fitted to a WO type rim for a pneumatic tire while being stretched, had a sufficient fitting force and did not come off during running.

Example 3 The canvas used in Example 2 was dipped in a mixture of an aqueous solution of an initial condensation product of resorcin and formalin and a synthetic rubber latex, and then heat-bonded in an oven at 150 ° C for 10 minutes. Was used as a tension body. Further, as the foamed elastomer, 60 parts by weight of natural rubber, SBR4
0 parts by weight, zinc white 5 parts by weight, foaming agent (DPT) 3.5 parts by weight, HAF black 40 parts by weight, sulfur 2.4 parts by weight,
Natural / S consisting of 1 part by weight of DM, 1 part by weight of antioxidant, 3 parts by weight of stearic acid, and 4 parts by weight of process oil.
A BR rubber compound was used.

Using the same mold as in Example 1, after winding the above tensile body around the inner peripheral surface of one of the split molds, the width was 18 mm and the thickness was 3 mm.
The above unvulcanized rubber compound having a length of 0 mm and a length of 1870 mm was wound in an annular shape and the mold was closed. This mold is heated by hot plate press 14
It was heated at 5 ° C for 15 minutes and vulcanized to obtain a foam rubber non-puncture bicycle tire. This tire, which was fitted to a WO type rim for a pneumatic tire while being stretched, had a sufficient fitting force and did not come off during running.

Comparative Example 1 Using the mold of Example 1, the diameter is 590 mm and the thickness is 0.88.
A non-puncture bicycle tire made of urethane foam was obtained in the same manner as in Example 1 except that the mm wire was coated with the liquid compound obtained by removing water from the urethane compound shown in Table 1 and the three strips were coiled. With this tire, the elongation of the rope was so small that it could not be fitted to the WO type rim for a pneumatic tire.

Comparative Example 2 A non-puncture bicycle tire made of urethane foam was obtained in the same manner as in Example 1 without adding a tension member. This was fitted to a WO type rim for a pneumatic tire while being stretched, but the fitting was insufficient and the rim could not be easily separated from the rim for running.

[0026]

INDUSTRIAL APPLICABILITY As described above, the non-puncture bicycle tire of the present invention is made of a material that is lightweight, has a foamed elastomer having excellent cushioning properties for absorbing the impact from the road surface, and has a large recovery force when the tensile stress is released. By integrally laminating the tension members, there is an effect that the force for fitting to the rim is increased and the detachment of the tire during traveling can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a non-puncture bicycle tire according to the present invention.

FIG. 2 is a sectional view of another non-puncture bicycle tire according to the present invention.

FIG. 3 is a cross-sectional view of a non-puncture bicycle tire manufacturing apparatus according to the present invention.

FIG. 4 shows a part of a partially enlarged view of FIG.

[Explanation of symbols]

 1 Non-punk bicycle tire 2 Tread part 3 Cushion part 4 Wheel mounting part 5 Tensile body

Claims (2)

[Claims] 1. A non-puncture bicycle tire having a tread portion, a cushion portion, and a protruding wheel mounting portion made of foamed elastomer, wherein the inner peripheral surface of the wheel mounting portion is selected from ropes, woven fabrics, and non-woven fabrics made of organic fibers. The tensile strength of the tensile body has a tensile elongation of 3.0% or more at break, and a strain recovery characteristic of 1.0% or more when the tensile stress is released, and 50 kg or more. A non-puncture bicycle tire characterized by having the following tensile strength. 2. The tire for a non-punctured bicycle according to claim 1, wherein the tensile body is laminated on the inner peripheral surface of the wheel mounting portion.